In the manufacture of cut-pile velours on knitting machines, the plush tucks tensioned in a loop-like manner are cut open by suitable cutting tools directly on the machine. In this connection reference is made to German Patent No. 11 53 482 which discloses a circular knitting machine for the manufacture of plush products. The machine includes a dial provided with guide grooves into which plush sinkers are inserted. The plush thread, guided by latch needles of the needle cylinder, is knocked over and looped by the plush sinkers. Each plush sinker has a cutting portion provided with an inward-directed cutting edge which cooperates in a scissors-like manner with an outward-directed cutting edge of a stationary cutting sinker.
Aside from the manufacture of cut-pile velours, in loop-forming textile machines the need occasionally also arises for other reasons to sever individual threads during the knitting process. In this connection reference is made to German Offenlegungsschrift (application published without examination) No. 20 03 301 which describes a circular knitting machine for stockings. The circular knitting machine operates with cutting needles which are inserted into the needle grooves of the needle cylinder. The cutting needles are formed as latch needles which have on their shank a ground, razor-sharp cutting edge oriented at an inclination to the longitudinal direction of the shank. As the needles move out into their cutting position, the cutting edge severs the loop suspended from the shank.
Cutting needles without a device for closing the hook, such as latches or the like, are described in German Patent No. 44 02 707 C2. At a shank location spaced from the hook, the cutting needle is provided with a cutting edge oriented at an inclination to the longitudinal direction of the shank. The cutting edge is ground to a wavy shape which increases the service life of the cutting needle.
The service life of the cutting needle is determined by its cutting edge. It is, accordingly, the object of the invention to further improve the cutting edge.